As the standard of our life advances, the methods of using daily commodities such as beauty treatment kits, and personal sanitary and bath products indispensable to our life are improved according to the advancement of related technologies. For example, shampoo has evolved from shampoo powder to bottled liquid shampoo, and users just need to gently press the bottle to draw liquid shampoo. The major core of these products resides on the apparatus of drawing liquid shampoo or hair gel. This type of pump drawing apparatus simply requires users to press a pull handle or a press handle to draw the liquid from a can or a bottle and obtain the desired result (such as sprays, foams, or liquid discharges).
Referring to FIG. 1 for the schematic view of a drawing structure of a prior art sprayer, the drawing structure 1 includes a casing pipe 12 coupled to the bottom of a nozzle 11, and the casing pipe 12 includes a drawing pipe 13, and the bottom of the drawing pipe 13 is coupled to a conical cover 14. The bottom of the conical cover 14 allows a pressing rod 15 to pass through, and the rear end of the pressing rod 15 presses against an end of a spring 16, and another end of the spring 16 has a ball 17, and a containing pipe 18 accommodates the drawing pipe 13, conical cover 14, pressing rod 15, spring 16, and ball 17 vertically and sequentially in the pipe, and the bottom of the containing pipe 18 includes a sucking pipe 19, and the whole drawing structure 1 is placed in a liquid can or bottle for drawing liquids.
The related drawing apparatuses for drawing liquid from a bottle have been disclosed in R.O.C. Pat. Application Nos. 094202158 and 088205688. The drawing apparatuses as disclosed in forgoing patented technology can only draw a liquid, but cannot simultaneously draw a liquid and a gas. In certain occasions that require the use of foams such as disk washing or hair shampooing, the foregoing drawing apparatuses are generally used for drawing detergent or shampoo, and users produce foams by rubbing the detergent or shampoo with hands. However, such arrangement usually cannot control the consuming quantity of detergent or shampoo. Particularly, excessive detergent may remain on kitchenware, if the kitchenware is not rinsed thoroughly, and finally may hurt human bodies. The same situation applies to shampoo, and the shampoo remained on our scalp may cause damages to our scalp.
In summation to the description above, a piston device and a fluid drawing apparatus and a foam producing apparatus using such piston device are required to provide the functions of drawing a liquid and a gas as well as appropriately producing foams easily, so as to overcome the shortcomings of the prior art.